I know how you feel, but I beg to differ.
I too have some mixed feelings, as I have always been a Gerald-Genta-Ingenieur fan, and own a few GG-inspired Ingenieurs. I am also sad to see the existing models being discontinued.
Before I comment further on my view regarding the new ingenieur series, let me share briefly my thoughts on the new Da Vinci. Granted the new Da Vinci series do not have the exotic-looking tonneau-shaped case, which are by the way, rather complicated and difficult to manufacture. Just for the record, despite IWC's earlier effort to make such a marvelous case, I think the series were not all that popular, and were not in high demand by consumers. People can argue all day long that the old Da Vinci looks so much better than the "boring" round-shaped watches such as the Portofino and the new Da Vinci. Nonetheless, the newer, round-shaped watches, are actually what many people willing to pay for with their money.
Also, there are a few pleasant surprises with the new Da Vinci. New movements aside, look at the applied numerals and the rotating lugs. These are not commonly found in other series of IWC. These, in my mind, still make the Da Vinci somewhat unique.
Now onto the new Ingenieur series. I think after many years of revising the Genta-inspired design, the outgoing Ingenieur series of watches no longer provide anyone with any surprises. IWC moved from a GG-inspired Ingenieur without crown-guard (3227) to one with it (3236). Then from plain gold, steel and titanium (read: GST) to exotic materials like ceramic and carbon fiber. IWC moved from bezel with a few holes to a few vulcanized bolt-heads. They added almost every complications (with the exception of minute repeater) to the ingenieurs series over the years, including digital-date perpetual calendar, dual-time, fly-back chronograph and even constant-force tourbillon. Grew from 42/44mm to 46mm. Frankly speaking, the more IWC puts in, the more "stale" and "bland" the ingenieur series start to become. I think the time for IWC to attempt to grab lowend market from Audemars Piguet Royal Oak and Hublot Big Bang is almost over.
one series of the ingenieur seems manage to sell rather well in the past. It ironically was not the GG-inspired ingenieurs. Instead, it was the vintage ingenieurs (3233). I think it is actually a bit wise after releasing GG-inspired ingenieurs for so long, IWC actually returns to its roots to come up with a redesign of the vintage ingenieur.
Also, in my opinion, the most well-received and purchased sports watch from IWC was neither the GG-inspired ingenieur nor the aquatimer. It was their precedessor, the GST series. For years fans from all over the world have been asking IWC to consider re-releasing a new GST series.
Look at the latest ingenieurs. Look at the one with metal bracelet. What does it resemble? I see signs and hints of the GST. I think IWC is on the edge of bringing the "GST" concept back.
Who knows if this new series of ingenieurs will succeed? it is still too early to tell. I think upcoming additions to the ones that are already announced will be even more interesting. (not that I know what is already in the sleeves of IWC's designers, namely Mr. Knoop's, but I think IWC has a few years to develop the new ingenieurs and make them more interesting/appealing).
Besides, if people are already feeling nostalgic about the outgoing Ingenieur series, I think there are plenty of existing stocks out there for fans to grab before they are sold out. Who knows, after a few years, when people are getting so used to the new ingenieur series, perhaps IWC could come up with a few "tribute to Gerald Genta" limited editions for the nostalgic fans.
To me, I'm glad that I have a few GG-inspired ingenieurs. I may get a few more if money and situation allows me to do so. I will also eagerly anticipate seeing the latest ingenieurs, and seeing what else to come down the road.